<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8"> 
	<title>Bootstrap 实例 - 下拉菜单（Dropdowns）</title>
	<link rel="stylesheet" href="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/css/bootstrap.min.css">
	<script src="http://cdn.static.runoob.com/libs/jquery/2.1.1/jquery.min.js"></script>
	<script src="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
    <div class="dropdown">
        <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown">
            主题
            <span class="caret"></span>

        </button>
        <ul class="dropdown-menu  pull-right" role="menu" aria-labelledby="dropdownMenu1">
                <li role="presentation" class="dropdown-header">下拉菜单标题</li>
            <li role="presentation">
                <a href="#" role="menuitem" tabindex="1">Java</a>                 
            </li>
            <li role="presentation">
                <a href="#" role="menuitem" tabindex="1">数据挖掘</a>
            </li>
            <li role="presentation">
                <a href="#" role="menuitem" tabindex="1">数据通信/网络</a>                 
            </li>
            <li role="presentation" class="divider"></li>
            <li role="presentation" class="dropdown-header">下拉菜单标题</li>
            <li role="presentation">
                <a href="#" role="menuitem" tabindex="1">分离的链接</a>
            </li>
        </ul>
    </div>


</body>
</html>